Asteroid nearly a mile wide just missed Earth

By Dean Murray via SWNS

An asteroid nearly a mile wide missed Earth last week.

Scientists tracked two close approaches by large space rocks on Thursday and Saturday.

The most recent, asteroid 2024 MK, was 500 feet wide, passing within about 184,000 miles (295,000 kilometers) of Earth.

The larger asteroid 2011 UL21 passed Earth on 27 June at a distance of 4.1 million miles (6.6 million kilometers), or about 17 times the distance between the Moon and Earth.

Spotted only 13 days before its closest approach to Earth, the object was classified as being potentially hazardous, but calculations of its future orbits show that it won’t pose a threat to our planet for the foreseeable future.

NASA says the Deep Space Network’s Goldstone planetary radar had "a busy few days" observing 2024 MK and 2011 UL21 as they passed us.

The space agency's Jet Propulsion Laboratory (JPL) in Southern California tracked them as they flew by our planet.

NASA says: "One turned out to have a little moon orbiting it, while the other had been discovered only 13 days before its closest approach to Earth.

"There was no risk of either near-Earth object impacting our planet, but the radar observations taken during these two close approaches will provide valuable practice for planetary defense, as well as information about their sizes, orbits, rotation, surface details, and clues as to their composition and formation."

Using the Deep Space Network’s 230-foot-wide (70-meter) Goldstone Solar System Radar, called Deep Space Station 14 (DSS-14), near Barstow, California, JPL scientists transmitted radio waves to the asteroid 2024 MK and received the reflected signals by the same antenna.

In addition to determining the asteroid is roughly spherical, they discovered that it’s a binary system: A smaller asteroid, or moonlet, orbits it from a distance of about 1.9 miles (3 kilometers).

Lance Benner, principal scientist at JPL who helped lead the observations, says: "It is thought that about two-thirds of asteroids of this size are binary systems, and their discovery is particularly important because we can use measurements of their relative positions to estimate their mutual orbits, masses, and densities, which provide key information about how they may have formed."

Two days later, on 29 June, the same team observed the asteroid 2024 MK pass our planet from a distance of only 184,000 miles (295,000 kilometers), or slightly more than three-quarters of the distance between the Moon and Earth.

About 500 feet (150 meters) wide, this asteroid appears to be elongated and angular, with prominent flat and rounded regions.

Close approaches of near-Earth objects the size of 2024 MK are relatively rare, occurring about every couple of decades, on average, so the JPL team sought to gather as much data about the object as possible.

"This was an extraordinary opportunity to investigate the physical properties and obtain detailed images of a near-Earth asteroid," said Benner.